This week's giveaway is in the EJB and other Java EE Technologies forum. We're giving away four copies of EJB 3 in Action and have Debu Panda, Reza Rahman, Ryan Cuprak, and Michael Remijan on-line! See this thread for details.
Just got an android phone and studying for SCJP, so thought I would combine both to learn Android and SCJP at the same time. Its 100% free. I intend to add more questions and beef up the functionality, so keep an eye on it.
At the moment 240 questions with answers and tips.